title: Experimental in situ exposure of the seagrass Posidonia oceanica (L.) Delile to 15 trace elements.
abstract: The Mediterranean seagrass Posidonia oceanica (L.) Delile has been used for trace element (TE) biomonitoring since decades ago. However, present informations for this bioindicator are limited mainly to plant TE levels, while virtually nothing is known about their fluxes through P. oceanica meadows. We therefore contaminated seagrass bed portions in situ at two experimental TE levels with a mix of 15 TEs (Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Mo, Ag, Cd, Pb and Bi) to study their uptake and loss kinetics in P. oceanica. Shoots immediately accumulated pollutants from the beginning of exposures. Once contaminations ended, TE concentrations came back to their original levels within two weeks, or at least showed a clear decrease. P. oceanica leaves exhibited different uptake kinetics depending on elements and leaf age: the younger growing leaves forming new tissues incorporated TEs more rapidly than the older senescent leaves. Leaf epiphytes also exhibited a net uptake of most TEs, partly similar to that of P. oceanica shoots. The principal route of TE uptake was through the water column, as no contamination of superficial sediments was observed. However, rhizomes indirectly accumulated many TEs during the overall experiments through leaf to rhizome translocation processes. This study thus experimentally confirmed that P. oceanica shoots are undoubtedly an excellent short-term bioindicator and that long-term accumulations could be recorded in P. oceanica rhizomes.
authors.affiliation: MARE Centre, Laboratory of Oceanology, University of Liège, Sart-Tilman, B6c, 4000 Liège, Belgium. jonathan.richir@alumni.ulg.ac.be
authors.forename: J
authors.initials: J
authors.lastname: Richir
authors.forename: N
authors.initials: N
authors.lastname: Luy
authors.forename: G
authors.initials: G
authors.lastname: Lepoint
authors.forename: E
authors.initials: E
authors.lastname: Rozet
authors.forename: A
authors.initials: A
authors.lastname: Alvera Azcarate
authors.forename: S
authors.initials: S
authors.lastname: Gobert
mesh_terms: D035961:Alismatales / Q000187:drug effects / Q000378:metabolism*; D004781:Environmental Exposure; D019015:Geologic Sediments / Q000737:chemistry; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism; D027343:Rhizome / Q000187:drug effects / Q000378:metabolism; D012623:Seawater / Q000737:chemistry; D014131:Trace Elements / Q000032:analysis / Q000378:metabolism* / Q000633:toxicity; D014874:Water Pollutants, Chemical / Q000378:metabolism* / Q000633:toxicity
chemical_list: D014131:Trace Elements; D014874:Water Pollutants, Chemical
keywords: In situ exposure; Kinetic; Posidonia oceanica; Trace element